An electrolaryngeal (EL) device provides a means of verbal communication for people who have either undergone a laryngectomy or are otherwise unable to use their larynx (for example, after a tracheotomy). These devices are typically implemented with a vibrating impulse source held against the neck.
Although some of these devices give users a choice of two frequency rates at which they can vibrate, most users find it cumbersome to switch between frequencies, even if a dial is provided for continuous pitch variation. In addition, most users cannot release and restart the device sufficiently quickly to produce the silence that is conventional between words in a spoken phrase.
As a result, the perceived overall quality of their speech is degraded by the presence of the device “buzzing” throughout each phrase. Furthermore, many EL voices have a “mechanical” or “tinny” quality, caused by an absence of low-frequency energy, and sometimes an excess at high frequencies, compared to a natural human voice.
Ordinarily, speakers, both normal and electrolaryngeal, close their mouths during inter-word intervals. This reduces the sound of the EL much during these times; the sound is noticeable merely because it is the only sound that the speaker is producing at the time.